1. Jawaban: B

1. (i)+(ii): x + z = 6; (i)−(ii): y = 3; (i)+(iii): x + y = 5 → x = 2, z = 4.
2. Cek (ii): 2 − 3 + 4 = 3 ✓. Jadi x = 2.

2. Jawaban: D

1. Sumbu simetri x = −b/2a = −(−6)/(2·1) = 3.

3. Jawaban: A

1. Terjemahan langsung tiap kalimat ke persamaan.
2. Sistem konsisten: x = 1.500, y = 4.500, z = 5.500.

4. Jawaban: C

1. (i)−(iii): J − M = −10; (ii) − 2×(iii): J + M = 30 → M = 20, J = 10, A = 30 (dalam ribuan).
2. Harga 1 kg mangga = Rp20.000,00. Verifikasi ketiga persamaan ✓.

5. Jawaban: C

1. x = 1, y = 2, z = 3 → x² + y² + z² = 1 + 4 + 9 = 14.

6. Jawaban: C

1. Maksimum di t = −b/2a = 20/10 = 2 detik.
2. h(2) = −5(4) + 20(2) = −20 + 40 = 20 m.

7. Jawaban: B

1. f(x) = a(x + 1)(x − 3); f(0) = a(1)(−3) = −3a = −6 → a = 2.
2. Jadi f(x) = 2(x² − 2x − 3) = 2x² − 4x − 6. Verifikasi akar & titik ✓.

8. Jawaban: E

1. Misal investasi pertama x. y = 2x; z − 6jt = x + y = 3x → z = 3x + 6jt.
2. Total: x + 2x + (3x + 6jt) = 48jt → 6x = 42jt → x = 7jt, y = 14jt, z = 27jt.

9. Jawaban: C

1. Misal sisi tegak x, sisi sejajar tembok y. 2x + y = 40 → y = 40 − 2x.
2. Luas L = x(40 − 2x), maksimum di x = 10, y = 20 → L = 200 m².

10. Jawaban: B

1. Akar −2 dan 5 → b = −(−2 + 5) = −3, c = (−2)(5) = −10, jadi f(x) = x² − 3x − 10.
2. Nilai minimum = −D/4a = −((−3)² − 4·1·(−10))/4 = −49/4 = −12,25.